CA1042591A - Bodying of organopolysiloxanes with diatomaceous earth and metal soap catalyst - Google Patents
Bodying of organopolysiloxanes with diatomaceous earth and metal soap catalystInfo
- Publication number
- CA1042591A CA1042591A CA215,690A CA215690A CA1042591A CA 1042591 A CA1042591 A CA 1042591A CA 215690 A CA215690 A CA 215690A CA 1042591 A CA1042591 A CA 1042591A
- Authority
- CA
- Canada
- Prior art keywords
- silanol
- organopolysiloxane
- mixture
- iron
- metal soap
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/06—Preparatory processes
- C08G77/08—Preparatory processes characterised by the catalysts used
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
- C08K5/098—Metal salts of carboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
- C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxyl groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/70—Siloxanes defined by use of the MDTQ nomenclature
Abstract
ABSTRACT OF THE DISCLOSURE
Silanol-containing organopoly-siloxane resins are bodied by effecting controlled condensation in admixture with diatomaceous earth and a metal soap catalyst. The bodied resins have improved heat life and superior cure rates.
Silanol-containing organopoly-siloxane resins are bodied by effecting controlled condensation in admixture with diatomaceous earth and a metal soap catalyst. The bodied resins have improved heat life and superior cure rates.
Description
1~2S91 8SI-1507 This invention relates to a method for building up the molecular weight of organopolysiloxane resins. More particularly, it concern~ bodying such resins in admixture with diatomaceous earth and a metal ~oap cataly~t.
Several methods have been available in the prior art for building up the vi~cosities of silanol-containing organopolysiloxane resins in a controlled manner. This proce~s, known as "bodying", is designed to increase the molecular weight of organopoly~iloxane hydrolyzate~ to make ~ -~
them re valuable in re~in applications. During bodying, condensation of silanol radicals are effected in the hydrolyzate to lengthen the shelf life and decrease the cure time. If bodyîng i8 not carried out in a well-controlled fashion, however, premature gellation of the organopolysiloxane resin will occur, and cause total 108~ of the batch.
Britton et al, U.S. patent 2,460,805 issued February 8, 1949, teach that organopolysiloxane polymsrs can be bodied with acid activated clays, such as bentonite and other hydrou~
aluminum silicates. Activation of the clay i8 accomplighed by heat treatment with strong acid~, namely sulfuric acid and phosphoric acid. On the other hand R.~. Meals and 4 P.N. Lewis, "Silicones", Rainhold Publishing Co., (1959), '4~ page 134, disclose that bodying can be carried out with metal ~oap catalyst~, such as zinc octoate.
~oth methods have di~advantages in practice, however.
Acid activated clay~ appear to function best only if the bodying temperature i9 raised to the order of 200C at which temperature proce~s control become~ difficult -- the more useful solvents boil wall below thi~, too; and, with either acid clay bodying as metal 80ap catalyzed bodying, the shelf life ~t 25C i9 often less than three months. Moreover, in ' ~ . . .
.: . . .
~ ZS91 all cases the cure time of the re~in is longer than would be desirable, often exceeding 20 hours or more, when the ro~in is combined with conventional curing catalysts, e.g., amines.
A much improved m~thod for bodying such resins is -~
disclo~ed in Merrill, U.S. patent 3,375,222 issued May 8, 1945 assigned to the assignee of the present application. In that method the silanol-containing resin is heated in the presence of a hydrogen chloride activated particulated siliceous material, e.g., diatomaceous earth, and the bodying is carried out efficiently at temperatures ~ubstantially lower than that reguired with acid activated clays. Moreover, becausQ no metal soap catalyst is used at all, the bodied resin i8 not contaminated, with metal ions which, in high amounts, can impair the stability of the cured resin, as well as substantially reduce its shelf life. - -Thé method of bodying resins described in the Merrill i, patent, while efficient, doe~ provide resins which still have t` 80me disadvantages, in common with all of the other silicone resins bodied by prior art procedures. Chief among these is .~, . . . . .
the need to add greater than 0.005% of catalytic metal on re~in ~olids to obtain a fast enough cure. However, all 1 such re~in~ catalyzed with the optimum amount, e.g., 0.03 to ¦ 0.06% as iron, degrade in les~ than one week at 250-300C.
It ha~ now been discovered that when ~ilanol-containing organopolysiloxane resins are bodies in admixture ~ with diatomaceous earth (preferably unactivated diatomaceous ¦ earth, that is, not acid activated) and a very low level of ~1 metal soap catalyst for silanol ~elf-conden~ation, then bodied Y re~ins will be obtained with superior proparties. Moreover, 3 30 when the resins are bodied according to this di~covery, then are further catalyzed with as much as 0.06% catalyst ~ ~Z591 calculated as metal, e.g., iron, they exhibit out~tandinq heat stability. Moreover, the cure rate i8 excellent: resins that would normally reguire the addition of 0.06% of eatalyst, e.g.,aq iron to obtain a cure time o less than 10 seconds, cure is less than five seconds -- without any added eatalyst --the only catalyst being the low, residual amount, e.g., 0.001~, as iron, used ~or bodying by the new method of this invention.
Aecording to this invention, there is provided a proeess for effeeting the eontrolled condensation of silanol radicals in a silanol-containing organopolysiloxane, which eomprises: (1) heating at a temperature of between 50C. and 250C., a mixture eomprising the silanol-containing organopolysiloxane, diatomaeeous earth in an amount of from 0.75 to 20% by weight of the silanol-eontaining organopoly- -siloxane and a metal soap catalyst in an amount of from 0.0005 to 0.002%, calculated as metal, by weight of the silanol-containing organopolysiloxane; and (2) recovering in -organopoly~iloxane from the resulting mixture of (1), leaving a vi~cosity higher than the silanol-containing organopoly-siloxane.
The silanol-eontaining organopoly~iloxane will -~
illustratively be a hydrolyzate of the formula (R)aSio4-a whe~e R i~ seleeted from a monovalent hydroearbon radical and a halogenated monovalent hydroearbon radieal and a has a valu~
of from 1 to 1.8, preferably from 1.25 to 1.75 inclusive.
Radieals ineluded by ~ are, typieally, alkyl and ehloroalkyl radicals, sueh as methyl, ehloroethyl, propyl, o~tyl, and the like, aryl and haloaryl radieals, sueh as , .
~4ZS91 phenyl, chlorophenyl, bromophenyl, dichlorophenyl, diphenyl, -naphthyl, tolyl, xylyl, and the like. R can be more than one radical, e.g., two or more of the foregoing. Preferably the organopolysiloxane will be a methylphenylpolysiloxane.
The silanol-containing material which i8 bodied according to this invention can be made, for example by -hydrolyzing an organohalosilane of the formula:
! ~R)bSiX4_b wherein R is as defined above, b i8 an integer equal to 1 or
Several methods have been available in the prior art for building up the vi~cosities of silanol-containing organopolysiloxane resins in a controlled manner. This proce~s, known as "bodying", is designed to increase the molecular weight of organopoly~iloxane hydrolyzate~ to make ~ -~
them re valuable in re~in applications. During bodying, condensation of silanol radicals are effected in the hydrolyzate to lengthen the shelf life and decrease the cure time. If bodyîng i8 not carried out in a well-controlled fashion, however, premature gellation of the organopolysiloxane resin will occur, and cause total 108~ of the batch.
Britton et al, U.S. patent 2,460,805 issued February 8, 1949, teach that organopolysiloxane polymsrs can be bodied with acid activated clays, such as bentonite and other hydrou~
aluminum silicates. Activation of the clay i8 accomplighed by heat treatment with strong acid~, namely sulfuric acid and phosphoric acid. On the other hand R.~. Meals and 4 P.N. Lewis, "Silicones", Rainhold Publishing Co., (1959), '4~ page 134, disclose that bodying can be carried out with metal ~oap catalyst~, such as zinc octoate.
~oth methods have di~advantages in practice, however.
Acid activated clay~ appear to function best only if the bodying temperature i9 raised to the order of 200C at which temperature proce~s control become~ difficult -- the more useful solvents boil wall below thi~, too; and, with either acid clay bodying as metal 80ap catalyzed bodying, the shelf life ~t 25C i9 often less than three months. Moreover, in ' ~ . . .
.: . . .
~ ZS91 all cases the cure time of the re~in is longer than would be desirable, often exceeding 20 hours or more, when the ro~in is combined with conventional curing catalysts, e.g., amines.
A much improved m~thod for bodying such resins is -~
disclo~ed in Merrill, U.S. patent 3,375,222 issued May 8, 1945 assigned to the assignee of the present application. In that method the silanol-containing resin is heated in the presence of a hydrogen chloride activated particulated siliceous material, e.g., diatomaceous earth, and the bodying is carried out efficiently at temperatures ~ubstantially lower than that reguired with acid activated clays. Moreover, becausQ no metal soap catalyst is used at all, the bodied resin i8 not contaminated, with metal ions which, in high amounts, can impair the stability of the cured resin, as well as substantially reduce its shelf life. - -Thé method of bodying resins described in the Merrill i, patent, while efficient, doe~ provide resins which still have t` 80me disadvantages, in common with all of the other silicone resins bodied by prior art procedures. Chief among these is .~, . . . . .
the need to add greater than 0.005% of catalytic metal on re~in ~olids to obtain a fast enough cure. However, all 1 such re~in~ catalyzed with the optimum amount, e.g., 0.03 to ¦ 0.06% as iron, degrade in les~ than one week at 250-300C.
It ha~ now been discovered that when ~ilanol-containing organopolysiloxane resins are bodies in admixture ~ with diatomaceous earth (preferably unactivated diatomaceous ¦ earth, that is, not acid activated) and a very low level of ~1 metal soap catalyst for silanol ~elf-conden~ation, then bodied Y re~ins will be obtained with superior proparties. Moreover, 3 30 when the resins are bodied according to this di~covery, then are further catalyzed with as much as 0.06% catalyst ~ ~Z591 calculated as metal, e.g., iron, they exhibit out~tandinq heat stability. Moreover, the cure rate i8 excellent: resins that would normally reguire the addition of 0.06% of eatalyst, e.g.,aq iron to obtain a cure time o less than 10 seconds, cure is less than five seconds -- without any added eatalyst --the only catalyst being the low, residual amount, e.g., 0.001~, as iron, used ~or bodying by the new method of this invention.
Aecording to this invention, there is provided a proeess for effeeting the eontrolled condensation of silanol radicals in a silanol-containing organopolysiloxane, which eomprises: (1) heating at a temperature of between 50C. and 250C., a mixture eomprising the silanol-containing organopolysiloxane, diatomaeeous earth in an amount of from 0.75 to 20% by weight of the silanol-eontaining organopoly- -siloxane and a metal soap catalyst in an amount of from 0.0005 to 0.002%, calculated as metal, by weight of the silanol-containing organopolysiloxane; and (2) recovering in -organopoly~iloxane from the resulting mixture of (1), leaving a vi~cosity higher than the silanol-containing organopoly-siloxane.
The silanol-eontaining organopoly~iloxane will -~
illustratively be a hydrolyzate of the formula (R)aSio4-a whe~e R i~ seleeted from a monovalent hydroearbon radical and a halogenated monovalent hydroearbon radieal and a has a valu~
of from 1 to 1.8, preferably from 1.25 to 1.75 inclusive.
Radieals ineluded by ~ are, typieally, alkyl and ehloroalkyl radicals, sueh as methyl, ehloroethyl, propyl, o~tyl, and the like, aryl and haloaryl radieals, sueh as , .
~4ZS91 phenyl, chlorophenyl, bromophenyl, dichlorophenyl, diphenyl, -naphthyl, tolyl, xylyl, and the like. R can be more than one radical, e.g., two or more of the foregoing. Preferably the organopolysiloxane will be a methylphenylpolysiloxane.
The silanol-containing material which i8 bodied according to this invention can be made, for example by -hydrolyzing an organohalosilane of the formula:
! ~R)bSiX4_b wherein R is as defined above, b i8 an integer equal to 1 or
2, and X is a halogen, e.g., chloro, bromo, etc. Specific -examples useful organohalosilanes are methyltrichloro~ilane, dimethyldichlorosilane, methyphenyldichlorosilane, phenyltri-chlorosilane, diphenyldichlorosilane, and the like.
Preferably, mixtures of the above-mentioned organo- --halosilanes will be employed to produce resins bodied in this invention. Hydrolysi3 of the mixture of halosilanes of the above formula can be carried out by well known methods. One description i8 found in Rochow, "Chemistry of the Silicone~' (2nd Edition), John Wiley & Sons, Inc., ~ew York, p.90-94.
Such procedures involve tho addition of water to the organo-i halo~ilane6 or mixtures thereof with aliphatic alcohol. One particularly usoful procedure involves hydrolysis in a two phase system using a water immi~sible organic ~olvent and -~r ~ ~ ~acetone in the media. This is de wribed in the ~h6~ patent ' of D.F. Merrill, No. ~6~, 99G, i~ued f~or~ 2 o" 9 7 asaigned to the assignoe of the present application. The pr~paration of Quch preferred starting materials will be described in detail in the Example~ hereinafter. Preferably the methylphenylpoly~iloxanes will be composed of chemically combined methylsiloxy unit3 and diphenylsiloxy unit~.
. . .
The diatomaceous earth i~ a form of particulated siliceous material containing silicon dioxide or its hydrates.
Unlike clays, it is substantially free of chemically combined aluminum. The diatomaceous earth is a heterogeneous ~olid material hsving a high surface area, of at least 0.2 m. /g.
Diatomaceous earth is also known as infusorial earth and/or siliceous earth, fossil flour and kieselguhn. It i8 COmpO8ed of siliceous fragments of various species of diatoms, and is ! a light gray to pale buff powder which i~ insoluble in water, i- 10acids and dilute alkali. It is commercially available from a r~d~ ~ a~r L s number of sources, e.g., under the ~dr~Nmu~ Celite and Super-Cell. A typically useful form is known as Celite 545, and is available ~rom Johns-Manville Corp.
,JI, It i~ important to use diatomaceous earth which has ;I not been pretreated or activated, especially with acid, and particularly with hydrochloric acid, in the present process.
~2 Any of the well known metal soap catalysts u~ed for ~i condensing silanol-containing organopoly~iloxane resin~ can be used herein. (See-Meals and Lewis, above). These can generally comprise a metal ~alt of an organic acid having greater than about five carbon atoms, preferably from 6 to 30 carbon atoms, e.g., capric, caproic, octoic, isooctoic, deconoic, octadecanoic, etc., in which the metal is an ionic form of iron, zinc, tin, cobalt, lead, nickel, cadmium, and the like. Preferably, the metal component will be iron, zinc, tin, cobalt, lead, nickel, cadmiu~ and the like. Preferably, the metal component will be iron, zinc, tin or cobalt.
Especially preferably, these will be used in the form of octoates. Most preferably the metal soap catalyst will be iron octoate.
~, .
~: . . ' :
l~ZS91 In practicing the invention, a mixture of the silanol-containing organopolysiloxane, the diatomaceous earth and the metal soap catalyst i~ heated The bodied organopolysiloxane is ~eparated at a higher viscosity.
The order of addition of the various ingredients to the bodying mixture, which can also include a suitable organic --solvent and the like, i9 not critical Preferably, the diatomaceous earth and metal soap cataly3t are added to an organic solvent solution of the silanol-containing organopoly- -siloxane resin. Especially preferably, any excess acidity in i the organic solvent solution will be removed, e.g , by a water wash, before adding the diatomaceous earth and the catalyst.
The diatomaceous earth can be u~ed in the bodying ~ mixture at from 0.75 to 5~ by weight of the organopoly- -:
`~ siloxane, and preferably from 0.75 to 20%. Suprlsingly, the advantageous result~ are not obtained with 0.5% of the diatomaceou~ earth. The best combination of efficiency and .~ . .
effectivenes~ i9 observed with 1% of unactivated diatomaceous earth, based on resin solids.
It is important to use an unusually low amount of the metal soap catalyst, the amount being calculated on the weight of contained metal and based on the weight of silanol-~ ,, .
~; containing organopolysiloxane in the mixture. The usaful amount will range fro~ about 0.0005 to about 0.00~%, calculated a~ metal, by weight of resin solids. The best combination of effectivene~s is seen at about 0.001%, as metal, based on resin solids. Below 0.0005%, the cure rate of the bodied ~ resin will be too 810w; and above 0.00~%, the heat stability
Preferably, mixtures of the above-mentioned organo- --halosilanes will be employed to produce resins bodied in this invention. Hydrolysi3 of the mixture of halosilanes of the above formula can be carried out by well known methods. One description i8 found in Rochow, "Chemistry of the Silicone~' (2nd Edition), John Wiley & Sons, Inc., ~ew York, p.90-94.
Such procedures involve tho addition of water to the organo-i halo~ilane6 or mixtures thereof with aliphatic alcohol. One particularly usoful procedure involves hydrolysis in a two phase system using a water immi~sible organic ~olvent and -~r ~ ~ ~acetone in the media. This is de wribed in the ~h6~ patent ' of D.F. Merrill, No. ~6~, 99G, i~ued f~or~ 2 o" 9 7 asaigned to the assignoe of the present application. The pr~paration of Quch preferred starting materials will be described in detail in the Example~ hereinafter. Preferably the methylphenylpoly~iloxanes will be composed of chemically combined methylsiloxy unit3 and diphenylsiloxy unit~.
. . .
The diatomaceous earth i~ a form of particulated siliceous material containing silicon dioxide or its hydrates.
Unlike clays, it is substantially free of chemically combined aluminum. The diatomaceous earth is a heterogeneous ~olid material hsving a high surface area, of at least 0.2 m. /g.
Diatomaceous earth is also known as infusorial earth and/or siliceous earth, fossil flour and kieselguhn. It i8 COmpO8ed of siliceous fragments of various species of diatoms, and is ! a light gray to pale buff powder which i~ insoluble in water, i- 10acids and dilute alkali. It is commercially available from a r~d~ ~ a~r L s number of sources, e.g., under the ~dr~Nmu~ Celite and Super-Cell. A typically useful form is known as Celite 545, and is available ~rom Johns-Manville Corp.
,JI, It i~ important to use diatomaceous earth which has ;I not been pretreated or activated, especially with acid, and particularly with hydrochloric acid, in the present process.
~2 Any of the well known metal soap catalysts u~ed for ~i condensing silanol-containing organopoly~iloxane resin~ can be used herein. (See-Meals and Lewis, above). These can generally comprise a metal ~alt of an organic acid having greater than about five carbon atoms, preferably from 6 to 30 carbon atoms, e.g., capric, caproic, octoic, isooctoic, deconoic, octadecanoic, etc., in which the metal is an ionic form of iron, zinc, tin, cobalt, lead, nickel, cadmium, and the like. Preferably, the metal component will be iron, zinc, tin, cobalt, lead, nickel, cadmiu~ and the like. Preferably, the metal component will be iron, zinc, tin or cobalt.
Especially preferably, these will be used in the form of octoates. Most preferably the metal soap catalyst will be iron octoate.
~, .
~: . . ' :
l~ZS91 In practicing the invention, a mixture of the silanol-containing organopolysiloxane, the diatomaceous earth and the metal soap catalyst i~ heated The bodied organopolysiloxane is ~eparated at a higher viscosity.
The order of addition of the various ingredients to the bodying mixture, which can also include a suitable organic --solvent and the like, i9 not critical Preferably, the diatomaceous earth and metal soap cataly3t are added to an organic solvent solution of the silanol-containing organopoly- -siloxane resin. Especially preferably, any excess acidity in i the organic solvent solution will be removed, e.g , by a water wash, before adding the diatomaceous earth and the catalyst.
The diatomaceous earth can be u~ed in the bodying ~ mixture at from 0.75 to 5~ by weight of the organopoly- -:
`~ siloxane, and preferably from 0.75 to 20%. Suprlsingly, the advantageous result~ are not obtained with 0.5% of the diatomaceou~ earth. The best combination of efficiency and .~ . .
effectivenes~ i9 observed with 1% of unactivated diatomaceous earth, based on resin solids.
It is important to use an unusually low amount of the metal soap catalyst, the amount being calculated on the weight of contained metal and based on the weight of silanol-~ ,, .
~; containing organopolysiloxane in the mixture. The usaful amount will range fro~ about 0.0005 to about 0.00~%, calculated a~ metal, by weight of resin solids. The best combination of effectivene~s is seen at about 0.001%, as metal, based on resin solids. Below 0.0005%, the cure rate of the bodied ~ resin will be too 810w; and above 0.00~%, the heat stability
3 of the bodied resin will tend to be adversely affected.
The mixture of silanol-containing organopolysiloxane, the diatomaceous earth and the metal soap catalyst can be '', ~ 6 , , ., .~ :
1~14;~591 heated to a temperature between 50C. and 250C. to effect the desired molecular weight increase in the resin. It i~
preferred to use a suitable organic solvent in the mixture to facilitate the polymerization and ~eparation of the re~ulting bodied organopolysiloxane. Suitable organic solvents include, for example, toluene, xylene, tetrahydrofuran, butyl acetate, butyl ether, trichloroethylene, and the like. Best results are obtained if a solution of the silanol-containing organo-polysiloxane resin i9 used in which the concentration of the resin i8 at best 50% by weight, based on the solution.
Preferably, a solution of organopolysiloxane resin in organic j ~olvent is employed having a concentration of 55 to 90h by -weight of resin, ba~ed on the total weight of the solution.
Body time can vary from as little as 1/2 hour to 24 hours or more depending on the nature of the silanol-containing organopolysiloxane, temperature, catalyst type and amount, surface area of the diatomaceous e~rth, the viscosity desired, and the like. A convenient method for determining the point at which the organopolysiloxane resin has reached a predeter-mined increase in viscosity is to use a Zahn viscosimeter.
The Zahn viscosimeter, a3 described in General Electric ' Review, No. 40,35-6 (1937) measures visco3ity by duration of i 10w through an orifice For example, if a ~o. 5 Zahn visco-- ;
imeter is used, the flow time, at reflux temperature~, of a solution of unbodied silanol-containing organopoly~iloxane at 50% ~olids, will typically range from 3 to 5 second~. After I bodying, the flow time under the same condieion~, will incraase i from 2 to 12-~old. This can correspond to an increase in resin viscosity of the bodied organopolysiloxane a9 compared to the unbodied resin, of 2 to 60-fold. At the desired visc08ity, based, e.g., on a predetermined Zahn flow time, heating is terminated and the mixture is cooled, e.g., to . ........... . .
, ... . .
, 1~4Z591 25-30C. The concentration of resin can be adjusted, e.g., by adding solvent, and any particulate material, e.g., diatomaceous earth can then be removed, e.g., by filtration.
While modifications of the Zahn techniques are valuable for following the process, especially precise control of the pr~cess i~ achieved if the viscosity of the unbodied resin, the bodied resin and the resin solutions is measured in a - -viscosimeter, such as one of the well known Bookfield-type.
These give viscosity values, relatively independently of shearing effect~, in centipoises at any convenient temperature, e.g., 25C. or 30& . It has been ound that the unbodied resin has a viscosity of from about 10 to about 50, and typically 20, centipoi~es (cps.) at 25C.; and that the --~
bodied resin has a viscosity of about 750 to 1,500, typically 1,000 cps. at 25C. After dilution to 5~% ~olids, the viscosity of the bodied resin will be from about 200 to about ~-700, typically 300 - 500 Cp9. at 25C.
The following examples are given by way of illustration and not limitation. All parts are by weight.
'J
V~scosities are at 25& .
~XAMPLE 1 , There is added to a solution of 1800 parts of acetone in 6000 parts of water, a silane blend con~isting of 970 parts of phenyltrichlorosilane, 740 parts of dimethyldichloro-silane, 290 parts of diphenyldichloro~ilane and 1800 part~ of toluene. Th~ rate of addition is controlled during 30 minutes to keep the maximum reaction temperature below 80C., then the mixture i~ stirred for 30 minutes more. The mixture is allowed to settle into two layers, and the organic layer is recovered by separating and drawing off the lower, acidic water layer. The acidity of the organic layer is reduced by adding 10% water, based on the organic solid~, to the - a -1~34ZS~l hydrolyzate and agitating. The resin-water mixture is heated and the toluene and water are atmospherically ~tripped off to 130C., leaving approximately 60% non-volatile resin-toluene mixture. To this are added 12 parts of diatomaceous earth (Celite 545) - 1% based on resin solids) and 0.2 parts of a 6% iron octoate solution (0.001% iron based on resin solids). The mixture is heated and stripped to 160C. The resin has a viscosity of 20 cps. at this point. The bodying is continued at this temperature by refluxing the solvent back to the heated resin and trapping off the water condensate.
The resin bodies to a viscosity endpoint of 1,000 cps. in 12 hours. The bodied resin is then cooled at about 25C., adjusted to 5~% solids with toluene and filtered to remove the -' particles of diatomaceous earth; vi~cosity is 400 cps.
i Samples of the above resin solution are catalyzed by the addition of 6% iron octoate solution to provide 0.005, `~ 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06% iron solids based on resin solids. Two grams of each catalyzed solution are ., placed in aluminum weighing cups and the solvent i8 evaporated.
~, 20 The resins are cured for heat life tests by exposing the cups 1~ to 50C. for one hour; 100C. ~or one hour; 150C for one hour and 200C. for 30 minutes. The resins are then aged in an oven at 250C. and removed daily for three months, cooled to 25C. and replaced in the 250& . oven. None of the specimens ! ~howed any thermal cracking or other evidence of degradation.
For co~parative purposes the same silane composition, hydrolyzed and then bodied with sulfuric acid activated clay by the prior art procedure and catalyzed with only 0.005% iron or resin ~
solids, thermal cracked and degraded in less than seven days. -There i8 added to 5600 parts of water, 1800 parts of xylene and 1800 parts of acetone, a silane blend consisting of .
_ g _ il~42S~l 670 parts of methyltrichlorosilane, 474 parts of phenyltrichloro-. .
silane, 290 parts of dimethyldichlorosilane and 566 parts of diphenyldichlorosilane. The rate of addition i9 controlled for 30 minutes maintaining the peak reaction temperature below 40C. The mixture is stirred for 30 minutes, allowed to settle, and the bottom ~queous acid layer is drawn off.
The acidity of the organic layer is reduced by adding water.
The resin-water mixture i9 heated and the solvent and water are removed by stripping under atmospheric conditions to 130C., leaving approximately 60% non volatile resin. There are added to the resin concentrate 12 parts of diatomaceous earth (1% ba~ed on resin solids) and 0.2 parts of a 6% iron octoate solution (0.001% iron based on resin solids). The mixture is stripped to 160& . and has a viscosity of 20 -centipoises at this point. The resin is then bodied at 160C.
by refluxing the solvent back to the mixture and trapping off -.:j the aqueous condensate. The resin i8 bodied to 1,000 cps.
viscosity in 90 minutes. The bodied resin is cooled and adju~ted to 5~% solids by adding xylene and then filtered to remove the particles of diatomaceous earth, final viscosity t . 400 Cp8 .
l The gel time of this resin i8 measured by placing ~ .
five drops of the solution from a dropper to form a puddle on a 200C. cure plate. The puddle i9 stirred constantly until , it i8 no longer liquid. The gel time, without any added 'f catalyst at all, i8 only three ~econd~. The same silaae :f compo~ition, hydrolyzed, thsn bodied with sulfuric acid activated clay by prior art methods, requires the addition of 0.06~ of iron based in resin solids to have a gel time of less than 10 seconds.
Based on the results shown above, it is apparent that ~ i the pre~ent invention provides an improved method for bodying silanol-containing organopolysiloxanes which is ~uperior to the methods of the prior art. The bodies resin ~olutions can be maintained at 25C. for many month~ without undergoing change. The short cure time is superior to that of the same resins which have been bodied with acid treated clay, with acid treated diatomaceous earth, and with metallic soaps.
In addition the resins bodies at described herein do not have to be filtered immediately to avoid continued bodying, as with acid activated clay. This avoids sliming on the filters and substantial economic losses in resin yields. It is al~o seen that product~ cured from resins bodied according to this invention have superior heat stability as compared to cured -products which have been bodied with acid activated clays and with metal soaps.
It is to be understood that many variations in the process of the present invention are possible in light of the i above detailed description without departing from the spirit or scope thereof. All aspects of the preqent invention are embraced within the full intended ~cope of the appended claims.
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The mixture of silanol-containing organopolysiloxane, the diatomaceous earth and the metal soap catalyst can be '', ~ 6 , , ., .~ :
1~14;~591 heated to a temperature between 50C. and 250C. to effect the desired molecular weight increase in the resin. It i~
preferred to use a suitable organic solvent in the mixture to facilitate the polymerization and ~eparation of the re~ulting bodied organopolysiloxane. Suitable organic solvents include, for example, toluene, xylene, tetrahydrofuran, butyl acetate, butyl ether, trichloroethylene, and the like. Best results are obtained if a solution of the silanol-containing organo-polysiloxane resin i9 used in which the concentration of the resin i8 at best 50% by weight, based on the solution.
Preferably, a solution of organopolysiloxane resin in organic j ~olvent is employed having a concentration of 55 to 90h by -weight of resin, ba~ed on the total weight of the solution.
Body time can vary from as little as 1/2 hour to 24 hours or more depending on the nature of the silanol-containing organopolysiloxane, temperature, catalyst type and amount, surface area of the diatomaceous e~rth, the viscosity desired, and the like. A convenient method for determining the point at which the organopolysiloxane resin has reached a predeter-mined increase in viscosity is to use a Zahn viscosimeter.
The Zahn viscosimeter, a3 described in General Electric ' Review, No. 40,35-6 (1937) measures visco3ity by duration of i 10w through an orifice For example, if a ~o. 5 Zahn visco-- ;
imeter is used, the flow time, at reflux temperature~, of a solution of unbodied silanol-containing organopoly~iloxane at 50% ~olids, will typically range from 3 to 5 second~. After I bodying, the flow time under the same condieion~, will incraase i from 2 to 12-~old. This can correspond to an increase in resin viscosity of the bodied organopolysiloxane a9 compared to the unbodied resin, of 2 to 60-fold. At the desired visc08ity, based, e.g., on a predetermined Zahn flow time, heating is terminated and the mixture is cooled, e.g., to . ........... . .
, ... . .
, 1~4Z591 25-30C. The concentration of resin can be adjusted, e.g., by adding solvent, and any particulate material, e.g., diatomaceous earth can then be removed, e.g., by filtration.
While modifications of the Zahn techniques are valuable for following the process, especially precise control of the pr~cess i~ achieved if the viscosity of the unbodied resin, the bodied resin and the resin solutions is measured in a - -viscosimeter, such as one of the well known Bookfield-type.
These give viscosity values, relatively independently of shearing effect~, in centipoises at any convenient temperature, e.g., 25C. or 30& . It has been ound that the unbodied resin has a viscosity of from about 10 to about 50, and typically 20, centipoi~es (cps.) at 25C.; and that the --~
bodied resin has a viscosity of about 750 to 1,500, typically 1,000 cps. at 25C. After dilution to 5~% ~olids, the viscosity of the bodied resin will be from about 200 to about ~-700, typically 300 - 500 Cp9. at 25C.
The following examples are given by way of illustration and not limitation. All parts are by weight.
'J
V~scosities are at 25& .
~XAMPLE 1 , There is added to a solution of 1800 parts of acetone in 6000 parts of water, a silane blend con~isting of 970 parts of phenyltrichlorosilane, 740 parts of dimethyldichloro-silane, 290 parts of diphenyldichloro~ilane and 1800 part~ of toluene. Th~ rate of addition is controlled during 30 minutes to keep the maximum reaction temperature below 80C., then the mixture i~ stirred for 30 minutes more. The mixture is allowed to settle into two layers, and the organic layer is recovered by separating and drawing off the lower, acidic water layer. The acidity of the organic layer is reduced by adding 10% water, based on the organic solid~, to the - a -1~34ZS~l hydrolyzate and agitating. The resin-water mixture is heated and the toluene and water are atmospherically ~tripped off to 130C., leaving approximately 60% non-volatile resin-toluene mixture. To this are added 12 parts of diatomaceous earth (Celite 545) - 1% based on resin solids) and 0.2 parts of a 6% iron octoate solution (0.001% iron based on resin solids). The mixture is heated and stripped to 160C. The resin has a viscosity of 20 cps. at this point. The bodying is continued at this temperature by refluxing the solvent back to the heated resin and trapping off the water condensate.
The resin bodies to a viscosity endpoint of 1,000 cps. in 12 hours. The bodied resin is then cooled at about 25C., adjusted to 5~% solids with toluene and filtered to remove the -' particles of diatomaceous earth; vi~cosity is 400 cps.
i Samples of the above resin solution are catalyzed by the addition of 6% iron octoate solution to provide 0.005, `~ 0.01, 0.02, 0.03, 0.04, 0.05 and 0.06% iron solids based on resin solids. Two grams of each catalyzed solution are ., placed in aluminum weighing cups and the solvent i8 evaporated.
~, 20 The resins are cured for heat life tests by exposing the cups 1~ to 50C. for one hour; 100C. ~or one hour; 150C for one hour and 200C. for 30 minutes. The resins are then aged in an oven at 250C. and removed daily for three months, cooled to 25C. and replaced in the 250& . oven. None of the specimens ! ~howed any thermal cracking or other evidence of degradation.
For co~parative purposes the same silane composition, hydrolyzed and then bodied with sulfuric acid activated clay by the prior art procedure and catalyzed with only 0.005% iron or resin ~
solids, thermal cracked and degraded in less than seven days. -There i8 added to 5600 parts of water, 1800 parts of xylene and 1800 parts of acetone, a silane blend consisting of .
_ g _ il~42S~l 670 parts of methyltrichlorosilane, 474 parts of phenyltrichloro-. .
silane, 290 parts of dimethyldichlorosilane and 566 parts of diphenyldichlorosilane. The rate of addition i9 controlled for 30 minutes maintaining the peak reaction temperature below 40C. The mixture is stirred for 30 minutes, allowed to settle, and the bottom ~queous acid layer is drawn off.
The acidity of the organic layer is reduced by adding water.
The resin-water mixture i9 heated and the solvent and water are removed by stripping under atmospheric conditions to 130C., leaving approximately 60% non volatile resin. There are added to the resin concentrate 12 parts of diatomaceous earth (1% ba~ed on resin solids) and 0.2 parts of a 6% iron octoate solution (0.001% iron based on resin solids). The mixture is stripped to 160& . and has a viscosity of 20 -centipoises at this point. The resin is then bodied at 160C.
by refluxing the solvent back to the mixture and trapping off -.:j the aqueous condensate. The resin i8 bodied to 1,000 cps.
viscosity in 90 minutes. The bodied resin is cooled and adju~ted to 5~% solids by adding xylene and then filtered to remove the particles of diatomaceous earth, final viscosity t . 400 Cp8 .
l The gel time of this resin i8 measured by placing ~ .
five drops of the solution from a dropper to form a puddle on a 200C. cure plate. The puddle i9 stirred constantly until , it i8 no longer liquid. The gel time, without any added 'f catalyst at all, i8 only three ~econd~. The same silaae :f compo~ition, hydrolyzed, thsn bodied with sulfuric acid activated clay by prior art methods, requires the addition of 0.06~ of iron based in resin solids to have a gel time of less than 10 seconds.
Based on the results shown above, it is apparent that ~ i the pre~ent invention provides an improved method for bodying silanol-containing organopolysiloxanes which is ~uperior to the methods of the prior art. The bodies resin ~olutions can be maintained at 25C. for many month~ without undergoing change. The short cure time is superior to that of the same resins which have been bodied with acid treated clay, with acid treated diatomaceous earth, and with metallic soaps.
In addition the resins bodies at described herein do not have to be filtered immediately to avoid continued bodying, as with acid activated clay. This avoids sliming on the filters and substantial economic losses in resin yields. It is al~o seen that product~ cured from resins bodied according to this invention have superior heat stability as compared to cured -products which have been bodied with acid activated clays and with metal soaps.
It is to be understood that many variations in the process of the present invention are possible in light of the i above detailed description without departing from the spirit or scope thereof. All aspects of the preqent invention are embraced within the full intended ~cope of the appended claims.
~' .
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! :
.1, , :, . ~. ~ -. .
: :
!
,~
. .
Claims (14)
1. A process for effecting the controlled condensation of silanol radicals in a silanol-containing organopolysiloxane to body said organopolysiloxane which comprises (1) heating at a temperature between 50°C. and 250°C., a mixture comprising said silanol-containing organo-polysiloxane, wherein the ratio of organo groups to siliconations is in the range 1 to 1.8 and wherein said organo groups are selected from monovalent hydrocarbyl groups and monovalent halogenated hydrocarbyl groups, diatomaceous earth in an amount of from 0.75 to 20% by weight of said silanol-containing organopolysiloxane and a metal soap catalyst in an amount of from 0.0005 to 0.002%, calculated as metal, by weight of said silanol-containing organopolysiloxane; and (2) recovering an organopolysiloxane from the resulting mixture of (1), having a viscosity higher than said silanol-containing organopolysiloxane.
2. A process as defined in claim 1 wherein the ratio of organogroups to silicon atoms is in the range of about 1.25 to about 1.75:1.
3. A process as defined in Claim 2 in which said mixture of (1) is an organic solvent solution comprising a major amount by weight of said silanol-containing organopolysiloxane.
4. A process as defined in claim 3 wherein said organopolysiloxane is a methyl phenylpolysiloxane composed of chemically combined phenyl siloxy units, diphenyl siloxy units and dimethyl siloxy units.
5. A process as defined in claim 3 wherein said organopolysiloxane is a methyl phenyl polysiloxane composed of chemically combined phenylsiloxy units, diphenyl siloxy units, methylsiloxy units and dimethylsiloxy units.
6. A process as defined in Claim 1, 2 or 3 wherein the metal component in said metal soap catalyst is selected from the group consisting of iron, zinc, tin and cobalt.
7. A process as defined in Claim 1, 2 or 3 wherein said metal soap catalyst is selected from the group consisting of iron octoate, zinc octoate, tin octoate and cobalt octoate.
8. A process as defined in Claim 1, 2 or 3 wherein said metal soap catalyst is iron octoate.
9. A process as defined in Claim 1, 4 or 5 wherein the amount of unactivated diatomaceous earth in the mixture of (1) is 1% by weight of said methylphenylpolysiloxane.
10. A process as defined in Claim 1, 4 or 5 wherein the metal soap catalyst in the mixture of (1) is iron octoate in an amount to provide 0.001% calculated as iron, based on the weight of said methylphenylpolysiloxane.
11. A process as defined in Claim 1, 4 or 5 wherein said metal soap catalyst comprises a metal component selected from the group consisting of an ionic form of iron, zinc, tin cobalt, nickel and cadmium and an organic acid component of from 6 to 30 carbon atoms.
12. A process as defined in Claim 1, 4 or 5 including the step of reducing any excess acidity in said silanol-containing organopolysiloxane prior to adding it to said mixture (1).
13. A process as defined in Claim 1, 4 or 5 wherein said recovered organopolysiloxane has a viscosity of about 1,000 centipoises.
14. A process for effecting the controlled condensation of silanol radicals in a silanol-containing organopolysiloxane, which comprises 1) heating at a temperature between 50°C. and 250°C., a mixture comprising said silanol-containing organo-polysiloxane, diatomaceous earth in an amount of from 0.75 to 20% by weight of said silanol-containing organopolysiloxane and a metal soap catalyst comprising a metal component selected from the group consisting of an ionic form of iron, zinc, tin, cobalt, nickel and cadmium and an organic acid component of from 6 to 30 carbon atoms in an amount of from 0.0005 to 0.002%, calculated as metal, by weight of said silanol-containing organopolysiloxane; and 2) recovering an organopolysiloxane from the resulting mixture of (1), having a viscosity higher than said silanol-containing organopolysiloxane which has an average ratio of from 1 to 1.8 organo radicals per silicon atom, selected from the group consisting of monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US424774A US3865766A (en) | 1973-12-14 | 1973-12-14 | Process for bodying organopolysiloxanes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1042591A true CA1042591A (en) | 1978-11-14 |
Family
ID=23683810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,690A Expired CA1042591A (en) | 1973-12-14 | 1974-12-09 | Bodying of organopolysiloxanes with diatomaceous earth and metal soap catalyst |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3865766A (en) |
| CA (1) | CA1042591A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4056492A (en) * | 1976-06-24 | 1977-11-01 | General Electric Company | Process for the production of a bodied silicone resin without the use of a catalyst |
| US4085084A (en) * | 1976-08-26 | 1978-04-18 | General Electric Company | Silicone resins having good thermal stability |
| US4386179A (en) * | 1980-05-07 | 1983-05-31 | Medical Research Associates, Ltd. | Hydrocarbon block copolymer with dispersed polysiloxane |
| US4328137A (en) * | 1980-06-16 | 1982-05-04 | General Electric Company | Process for rapidly bodying organopolysiloxane resins |
| US4698059A (en) * | 1983-12-09 | 1987-10-06 | Concept Polymer Technologies, Inc. | Enteral feeding tubes |
| US4578413A (en) * | 1983-12-21 | 1986-03-25 | Medical Research Associates, Ltd. #2 | Polymeric tubings comprising polysiloxane-modified elastomer compositions |
| JP6230727B2 (en) * | 2014-12-25 | 2017-11-15 | 日本山村硝子株式会社 | Phenyl-modified hybrid prepolymer, phenyl-modified polydimethylsiloxane-based hybrid prepolymer, phenyl-modified polydimethylsiloxane-based hybrid polymer, and methods for producing the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3375223A (en) * | 1964-10-01 | 1968-03-26 | Gen Electric | Method for polymerizing organopolysiloxanes |
| US3786015A (en) * | 1971-12-22 | 1974-01-15 | Gen Electric | Method for preparing fast curing silanol-containing organopolysiloxane resins and use of such resins |
-
1973
- 1973-12-14 US US424774A patent/US3865766A/en not_active Expired - Lifetime
-
1974
- 1974-12-09 CA CA215,690A patent/CA1042591A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US3865766A (en) | 1975-02-11 |
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